Orbital occupancy and hybridization in strained <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>SrV</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> epitaxial films
Mathieu Mirjolet, Hari Babu Vasili, Adrian Valadkhani, José Santiso, Vladislav Borisov, Pierluigi Gargiani, Manuel Valvidares, Roser Valentí, J. Fontcuberta
Abstract
Oxygen packaging in transition metal oxides determines the metal-oxygen hybridization and electronic occupation at metal orbitals. Strontium vanadate $(\mathrm{SrV}{\mathrm{O}}_{3})$, having a single electron in a $3d$ orbital, is thought to be the simplest example of strongly correlated metallic oxides. Here, we determine the effects of epitaxial strain on the electronic properties of $\mathrm{SrV}{\mathrm{O}}_{3}$ thin films, where the metal-oxide sublattice is corner connected. Using x-ray absorption and x-ray linear dichroism at the $\mathrm{V}\phantom{\rule{0.16em}{0ex}}{L}_{2,3}$ and O $K$ edges, it is observed that tensile or compressive epitaxial strain change the hierarchy of orbitals within the ${t}_{2g}$ and ${e}_{g}$ manifolds. Data show a remarkable $2p\ensuremath{-}3d$ hybridization, as well as a strain-induced reordering of the $\mathrm{V}\phantom{\rule{0.16em}{0ex}}3d({t}_{2g},{e}_{g})$ orbitals. The latter is itself accompanied by a consequent change of hybridization that modulates the hybrid ${\ensuremath{\pi}}^{*}$ and ${\ensuremath{\sigma}}^{*}$ orbitals and the carrier population at the metal ions, challenging a rigid band picture.